This invention relates to a device torquing or untorquing, in any sequence, visible or hidden nuts disposed on a common circle of centers. In particular, it relates to a torquing system and device capable of monitoring and measuring the following engineering parameters:
(a) Bolt location PA1 (b) Prevailing torque of nut to bolt PA1 (c) Applied torque PA1 (d) Applied turn angle PA1 (e) Breakaway torque
When coupled to a computer which is software driven with exact torquing requirements, said system and device will monitor the torquing requirements without human interpretation.
In the manufacture and/or assembly of various complex mechanical devices such as jet engines and the like, it is often necessary to assemble parts together by the use of bolts and nuts which must be torqued to exacting specifications. In addition, the problem is often made more complex by the number of bolts and nuts to be torqued and the blind location of said bolts and nuts.
In the past, hidden or remotely positioned nuts and bolts were fastened together inaccurately by elaborate mechanical linkages with gearbox and/or power transmission extensions which produced incalculable results in the torque applied at the nut. Input to output errors were also introduced due to linkage vector and gearing losses. In such situations, damage to the nut and/or bolt was realized because of improper positioning of the torque applying device primarily due to a blind location or a remotely situated combination of nuts and bolts. Cross-threading of nuts to bolts was also realized due to an inability to accurately position and install a nut to a bolt at said remote or blind location. In addition, the corners of nuts may be damaged and the threads of bolts stripped because of an inability to accurately measure the output torques in relation to the input torques or to measure the preferred turn angle torque due to gearing or linkage backlash.
Further, in a repetitive or sequential type of torquing requirement requiring controlled duplicated results at each bolt site, torquing accuracy becomes questionable because of the above-noted losses and an inability to reposition the mechanical linkage in the same way at different locations. This problem is easily understood by those skilled in the art with reference to the assembly of a jet engine which may require a definite "pattern" torquing sequence of sometimes in excess of 100 nuts and bolts arranged in a circular pattern.
While many bolt and nut fastening applications are blind and/or remotely located, many are also located in confined areas which precludes the use of standard geared or linkage type torquing devices. In the past, said standard devices were incapable of applying a required torque in a confined area due to the contact ratios or the gearing required to operate in said confined areas. In these situations, the use of small diameter gears with a small number of teeth causes the tips of the gear teeth to dig into the radial flank of the pinion, thus causing tooth breakage and poor efficiency and thereby eliminating many torquing applications on particular size bolts in confined areas.